Electromagnet



Dec. 26, 1933.

E. MCAFEE ELECTROMAGNET Filed Oct. 5, 1931 INVENTOR,

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Patented Dec. 26,

ELECTROMAGNET Ernest McAf ea Kansas City, half to George W. Meyer,

Mo., assignor of one- Kansas City, Mo.

Application October 5, 1931. SerialNo. 566,979

lClaim. (curs-cs1) This invention relatesto improvements in electromagnets and particularly-to an electro:

magnet operable by alternating current.

The principal object of this invention is the provision of an electromagnet having a laminated magnetic pole piece in which is embedded a coil in parallel relation with the laminations of said pole piece.

Another object of thepresent invention is the provision of an electromagnetf constructed in such a manner as to be effectually magnetized when alternating current is being passed throughthe coil or coils contained therein.

Other objects of this invention are the provision of an electromagnet that is simple in construction, effective in operation and inexpensive to install, due to the elimination of the usual rectifier which is now being used withthe commercial electromagnet when alternating current is used. I

Reference will now which: i e I Figure 1 is a plane view of an electromagnet embodying this invention. 7

Fig. 2 is a sectional view taken 'on line 11-11 ofFig.1,and'

Fig. 3 is a plane view of a modified form of the be had to the drawing, in

electromagnet constructed for use witha poly- I phase current;

In the drawing, likereference characters designate similar parts throughout the several views, and the numeral loindicates a pole piece made up of a series of parallel, insulated laminations 12 of a suitable magnetic material, such as iron, and having a closed coil-receiving groove 14 formed therein for the reception of a coil of insulated conductor wire 16. The coil of wire is so positioned in the pole piece 10 that the strands of wire making up the coil are in sub stantially parallel relation with the laminations of the pole piece. The groove 14 does not extend through all of the laminations of the series, thereby presenting a laminated connection between the inner portion 18 of the case and the outer portion 20' thereof.

Since the laminations 12 arepreferably made up of rather thin material, it is deemed advisable to provide relatively thick laminations on the outer surfaces to serve as a protective covering. Bolts 22 arepassed through holes formed through the laminationsand serve'to hold the same in fixed relative position. The bolts are provided with countersunk heads and are positioned at the phase. l V Furthermore, this magnet will not become ex- .ends of the coil through the intermediacy of conductors 24 and 25 are connected to any suitable 1 supply of alternating current throughline wires 26 and 28. The polarity of the pole portions 18 and 20 is determined by the direction of the flow of the current in coil 16, magnetic flux depends to a large extent on the ampere turns of the coil. When it is desired to use thisel ectromagnet with a polyphase current, it is necessary that the windings be changedto meet the varying conditions. The magnet shown in Fig. 3 is suitable for use with a three-phase This type of alternating current electromagnet I when properly proportioned will produce sub-" stantially uniform magnetic flux through the entire pole surfaces as long as the coil is being supplied .with alternating current of proper cessively'heated. However, care must be taken in' winding the coil to compensate for theinductive kick when the coil is opened. It isapparent that this electromagnet is adapted for commercial use where only an alternating current is available without the use of a motor generator orany type of rectifier which is now necessarily used. The principal features of this type of electromagnet are well suited for use in many electrical appliances suchas motors, etc.

Whilethe preferred forms of this invention have been shown and described, it is apparent that many modifications might be made without departing from the scope of the appended claim.

Having thus described the invention, what is alsothe strength of the current. The pole piece 30 is provided with two I claimed as'new and desired to be secured by Letters Patent isz' An electromagnet comprising a laminatedpole piece having parallel grooves formed in onejface thereof; coils mounted in said grooves in parallel relation with the laminations of said pole piece, I

whereby when an alternating electric current is passed through'said coils, said pole pieces will s be magnetized.

' ERNEST MCAFEE.

pole surface to presentv a smooth contacting surface for the armature or material to be attracted;

When used for certain purposes, it is obvious that the entire magnet or parts thereof might be covered with an electric insulating material for the purpose of protecting the parts and to preclude to alarge extent, possible fire hazards. The 

